Industrial furnace



June 26, 1945. K. w. STOOKEY INDUSTRIAL FURNACE Filed Feb. 10, 1943 a m k M m M my W W MA 5 \I\ um M w: NW m 2 .4 j M Patented June 26, 1945 UNITED STATES PATENT form-cc INDUSTRIAL FURNACE Kenneth W. Stookey, Cleveland, Ohio, assignorv to The Gas Machinery Company;,(3levelandi,Qliio, a corporation of Ohio Application February 10, 19%3,.S erial3N0. 475,365

6 Claims.

The invention particularly relates to improvements in industrial furnaces of .various types, and is concerned primarily with improved vapor-removing mechanism that is incorporated with the furnace structure to prevent vapors from a li uid sealing medium coming into contact with the furnace charge. The invention is illustrated herein by a showing and description of a rotary forging furnace with which the improvements areincorporated;

Several advantages attach to the invention:

It can be installed on any liquid sealed portion of. a; furnace toremove Vapors from the sealns nedi m- It obviates glaring. weaknesses in the furnace wall induced by certain other structures provided f hQ1' .8IIl V l P 13 0 65- lt enablescertain operating economies to be effected,

It pro ides a onst nt su ich an easily and definitely be varied to suit varying conditions.

Other and) la e ad anta es ue to the i stant improvements in industrial furnaces will be hereinafter mentioned by reference to the following description and the accompanying drawmg.

The annexed drawing and the following description set forth in detail certain means illustrating the improved industrial furnace, such means constituting, however, only one of the various forms in which the principle of the invention may be embodied.

In said annexed drawing:

Figure 1 is a vertical axial section of a rotary forging furnace with which the invention is inco n a ed;

Figure 2. is a plan section, taken in part from the planes indicated by the line 2A'-.2A, Figure 1; in part from the plane indicated by the line 2B-..-2B; and in part from the plane indicated by the line 2C2C;

Figure 3 s a e on an e ar ed ca of on of the Suction nozzles shown in Figure l; and

Figure 4 is a plan view of the suction nozzle shown in Figure 3.

Referring to the. annexed drawing in which the same parts are indicated by the same respective numbers in the several views, an oil or gas-fired rotary forging furnace i has a wall and dome str ure su roun n he r nd mpr s n an exterior side Wall 2 combined with a dome 3, the hearth being shown herein as a rotating table 4, the assembly providing a combustion chamber 5 between the dome 3 and table 4, all as it well understoodby those. versed in the art. The table 4 has clearance. from. the side wall 2 as indicated by the space 6.. Waste gas'fiues l are formed in he sidewall 2. and: communicate with the combustion chamber 5 through ports it whereby the waste products in the combustion chambert are withdrawn. therefrom. A water seal casing [3, in the form. of; an, annular trough, for a waterseal l2, surrounds. and. is secured to the rotatable table 4, preferably being built integrally with th table. casing. The clearance area 6 opens at its; bottom. into. the space above the water seal I2. since the seal trough l:3.is supported by the rotatable table 4, it can beand isfextended outwardly of the. furnace wall 2 and thus permits easy cleaning of: the water trough I3 since its outer part is. easily reached.

' The main. support for the side wall and dome s ltucture and the rotatable table 4 isa sub-base 14. formed. of I.-beams. and. mounted upon these beams, in a manner not. shown, are vertical 1- bean is l8 which form bases. for jack screws I5 mounted thereon. and cooperating with nuts Hi welded to horizontal-plate portions "5 ofhousings it which enclose. the upper ends of the I- beams l8 and upon the side surfaces of which they are slidable. The housings Iii are welded to the steel casing of the furnace wall 22. Thus, the furnace, side wall and dome structure can be vertically adjusted, relatively. to the rotating table 4, and the table clearance space 8 varied in crosssectional area, since the. spaced opposed surfaces of the furnace wall 2. and the hearth 4 defining the clearance area- 6 are sloped and are also substantially parallel, as shown and described in the patent on. Industrial furnaces, of Lazenby C. Hamlipk, No. 2,316,580. I

Other features. of the furnace with which the invention. is incorporated and shown in the accompanying drawing, to. which reference will. be

here briefly made, and which are more or less standard, include burners 22' for firing the furnace, a charge and discharge opening 23, an air curtain 24, a waterecooled shield 25, a seal over-' flow pipe 25, a lifting lug 21 for manipulating the wall and dome structure, a lifting lug 28 for furnaces of the character herein under co'nsidarea adjacently above the seal eration the vapors from the liquid seal, which kind of seal is most satisfactory for certain types of furnaces, for instance rotary and car-type furnaces, be prevented from entering the combustion chamber 5. In man types of furnaces including the types just specifically mentioned, it is also highly important that the entrance of infiltered atmospheric air to the combustion or heating chambers be prevented. If the entrance of liquid vapors and atmospheric air can be prevented, the maintenance of a constant furnace atmosphere is thereby better insured, with the production of quality products and without the use of an excessive amount of fuel. Particularly,

the scaling of the stock and surface decarburiza tion thereof are prevented. In the form of furnace shown in the accompanying drawi the slugs or stock are carried by the rotatinghearth 4 from a charging opening to a, discharge opening during the heating operation, as is well known to those skilled in the art, the charging and discharging of the stock oftentimes being effected through the same opening, as is true of the opening 23 shown for purposes of illustration in the accompanying drawing.

Various expedients have been devised for preventing entrance to the combustion chamber of seal vapors and atmospheric air, amongst which have been the provision of a wall duct adjacent the bottom of the table clearance area and communicating with the waste product vents, and also the provision of somewhat deeper waste product vents which communicate through ports in the side wall with the clearance area substantially below the upper level of the hearth. These expedients have not provided a constant draw of the vapors and air, nor one which could be easily and definitely controlled. Furthermore, the provision of an extra and lower vapor and air withdrawing duct adds a glaring weakness to the wall section or tile cored therefor.

The improvements which are presented in the instant application obviate the disadvantages just mentioned and, furthermore, produce operating economies which will be hereinafter fully de scribed.

For withdrawing the seal vapors according to the instant invention, a plurality of nozzles l'l, preferably of the shallow and wide-mouthed formation shown in Figures 3 and 4, are pro-- vided, of sufficient size and in whatever spacing are found suitable and necessary, which nozzles 11 intersect the dip plate H depending from the furnace side wall 2 into the seal 12 and tap the i2. Pipes l9 leading to these nozzles l1 communicate with a header pipe which surrounds the furnace I adjacently exteriorly of the side wall 2, and which in turn communicates through a pipe 2! with a Venturi section I0 in a pipe I0 leading from the motor-operated blower 9. A valve I0 in the pipe It serves to control the intensity of the suction and a valve H in the pipe 2| serves to throttle the suction. If suitable pressure burners are used for heating the furnace, the power for aspirating by the nozzles I! can be obtained by using low pressure air from the blower furnishing combustion air; for instance, from the combustion-air-furnishing pipe 34. Otherwise, low pressure air for aspirating can be obtained from any other suitable device or source, or compressed air or steam can be used. In the event that a deoxidizing or carburizing controlled atmosphere is used in which gases are withdrawn with the water vapors, an eX-hauster could be used, and

then the gases dehydrated and purified and returned to the furnace.

It is evident that the described mechanism would provide a constant draw throughout the entire heating and combustion ranges. This draw would be independent of the method of firing the furnace. The draw can be easily and definitely controlled to suit particular conditions.

Inasmuch as a positive and complete removal of the vapors is effected over a high range of temperatures, less sealing medium need be used since higher temperatures can be permitted and the vapors still adequately removed. This results in a reduction of water cost for the seal; also, a savings in pumping and cooling charges, if recirculated water is used. When oil or some such other sealing medium is utilized, which must be recirculated and cooled, a reduction in oil cost and pumping and cooling charges is effected.

The unimpaired wall structure adds considerable strength permitting a wall overhang which prevents considerable heat loss by radiation.

Also, the invention is applicable, to eliminate sand or othertype seals, with the advantages noted, to types of furnaces, such as electric furnaces, in which a liquid type of sealing is not otherwise so essential.

-What I claim is:

1. An industrial furnace having an enclosing wall and dome structure, and a hearth spaced from the wall forming a combustion chamber above the hearth, the combustion chamber communicating with the space between the wall and hearth, waste gas flues communicating with the combustion chamber, means for rotating the hearth, a liquid seal exteriorly of the hearth and below said space, a dip plate depending from the wall into the seal, a series of spaced pipes intersecting the dip plate and tapping the area adjacently above the liquid seal, and a suction device communicating with the outer ends of the pipes.

2. An industrial furnace having an enclosing wall anddcme structure, and a hearth spaced from the wall forming a combustion chamber above the hearth, the opposed wall and hearth surfaces being sloped and substantially paralle the combination chamber communicating with the space between the wall and hearth, waste gas lines communicating with the combustion chamber, means for rotating the hearth, means for raising and lowering the wall and dome structure, a liquid seal exteriorly of the hearth and below said space, a dip plate depending from the wall into the seal, a series of spaced pipes intersecting the clip plate and tapping the area adjacently above the liquid seal, a header communicating with the outer outer ends of the pipes,

a blower, an open-ended outlet pipe from the latter, and a valve-controlled pipe communicating at one end with the header and at the other end intersecting the outlet pipe.

3. An industrial furnace having an enclosing wall and dome structure, and a hearth spaced from the wall forming a combustion chamber above the hearth, the combustion chamber corrmunicating with the space between the wall and hearth, awater seal for said space, waste gas flues communicating with the combustion chamher, a valve-controlled conduit extended from exteriorly of and below the Wall and tapping the area adjacently above the water seal, and a valve-controlled Venturi-type aspirating device with which the outer end of the conduit communicates.

4. An industrial furnace having an enclosing Wall and dome structure, and a hearth spaced from the wall forming a combustion chamber above the hearth, the combustion chamber communicating with the space between the wall and hearth, a water seal for said space, waste gas fiues communicating with the combustion chamber, a valve-controlled conduit extended from exteriorly of and below the wall and tapping the area adjacently above the water seal, burners discharging into the combustion chamber, a blower having an outlet furnishing combustion air to the burners, and a valve-controlled open ended pipe communicating with the outlet between the blower and the burners, said conduit at its outer end communicating with the pipe.

5. An industrial furnace having relatively movable parts and formed with a combustion chamber, waste gas lines tapping the combustion chamher, an opening between the furnace parts having communication With the combustion chamber, a liquid seal for the opening, and a pipe passed into the furnace exteriorly of the relatively movable parts thereof and having an inner end portion tapping the area adjacent the chamber side of the liquid seal, said pipe exteriorly of the furnace wall communicating with a suction-producing device.

6. An industrial furnace having a wall and dome structure enclosing a combustion chamber, I

a hearth spaced from the wall and disposed below the combustion chamber, the latter communicating with the space between the wall and hearth, waste gas fiues tapping the combustion chamber, means for rotating the hearth, a liquid seal surrounding the hearth, said space communicating with the seal, a dip plate depending from the wall into the seal, burners for firing the furnace, a. combustion air pipe communicating with the burners, a blower effective upon said pipe,

an open-ended pipe communicating with the first-mentioned pipe between the blower and the burners and having a Venturi section, a series of pipes intersectin the dip plate and tapping the area adjacently above the liquid seal, a header for said series of pipes, and a, pipe communicating at one end with the header and tapping the Venturi section with its opposite end.

KENNETH W. STOOKEY. 

